Models for the size and shape of the earth's magnetopause and bow shock

Abstract

New models for the size and shape of the Earth's magnetopause and bow shock are derived, based on a criterion for selecting the crossing events and their corresponding up-stream solar wind parameters. In this study, we emphasize the importance of accurate interplanetary parameters for, predicting the size and shape of the magnetopause and bow shock. The time lag of the solar wind between the solar wind monitor and the location ofcrossings is carefully considered, ensuring more reliable up-stream solar wind parameters. With this database new functional forms for the magnetopause and bow shock surfaces are deduced. In this paper, we briefly present the preliminary results. For a given up-stream solar wind dynamic pressure Dp, an IMF norths-south compoent Bz, a solar wind β and a magnetosconic mach number Mms, the parameters that describe the magnetopause and bow shock surfaces ro and α can be expressed in terms of a set of coefficients determined with a multi-parameter fitting. Applications of these models to extreme solar wind conditions are demonstrated. For convenience, we have assumed that ro, Bz and Dp retain their units, except in equations where they are normalized by 1 RE(Earth radius), 1 nT and 1 nPa, respectively.